 (defn- prune-refer
   [refer-clause prefix used-syms]
   (map #(-> (str/split % #"/") second symbol)
-       (filter (into #{} used-syms)
+       (filter (set used-syms)
                (map #(str prefix "/" %) refer-clause))))
 
 (defn- remove-unused


(defn remove-unused-imports
  [symbols-in-use imports]
  (filter (into #{} symbols-in-use) imports))

(defn- remove-unused-requires [symbols-in-use libspecs]
  (map (partial remove-unused-syms-and-specs symbols-in-use) libspecs))

      (get-var-name node)))

(defn- used-vars
  "Finds used functions and classes"
  [ast]
  (->> ast
       (map nodes)
